jpugh99 :
I just got an EVO 850 250gb, and I was wondering if I could deactivate the product key on my HDD so I can use it on my SSD.
If all you are doing is changing the drive, no 'deactivation' needed.
Just install the OS on the new drive.
When it all works properly on the new drive, wipe the old drive.
Or, if the situation permits, consider a migration from the old drive to the new drive.